I guess I assumed that wherever you were residing when the shelter in place was issued is where you stayed. If I keep changing where I shelter in place then it seems like that defeats the purpose to me.
Not really. It's about minimizing contact with people. Outside of truly remote rural areas, it's assumed that the virus is basically everywhere. And even in the NYC metro area (8.6M people), confirmed case counts of 75K suggest that fewer than 1 in 100 people has a confirmed case - and that's comparing JUST the population of NYC, where we don't know that all 75K cases are NYC versus the rest of the state.
If you combine NY, NJ, CT and PA case counts (~100K), assuming
every case in every one of those states is
only in the NYC metro, and compare them against the NYC metro area population in total (23M), that's one person in less than 200 having a confirmed case.
So you assume that if you're asymptomatic, you're trying to avoid becoming infected more than you're trying to avoid spreading infection.
Obviously you don't want to constantly go back and forth from place to place, and you don't want to go to a place with fewer restrictions just to go galavanting out and about. But I think the risks of moving from one place to another, THEN staying there and sheltering in that place, are minimal.